1. Field of the Invention
The present invention relates to a folder type portable device, and more particularly, to a folder driving device for a portable device in which cam couplers are mounted in a hinge housing to improve assemblability and matchability of component parts.
2. Description of the Related Art
Generally, portable devices are classified, in terms of configuration, into a bar type in which number and function buttons are exposed to the outside, a flip type which has a cover for protecting number and function buttons, and a folder type which can be folded to be shortened in length to a half. As portable devices trend toward miniaturization, folder type portable devices are widely used throughout the world.
As shown in FIG. 1, a folder type portable device largely comprises a body element 10 and a folder 20. The body element 10 has number and function buttons 12 and a microphone. Various control units for enabling transmission and receipt of communication are built in the body element 10, and a battery pack is attached to a rear surface of the body element 10.
The folder 20 has a display window 22 for displaying various telephone-call information items and functional information items, and a speaker. Other various component parts are built in the folder 20.
In the folder type portable device, the folder 20 is connected to the body element 10 by hinge means that is composed of a shaft support part 16 and a hinge housing 25. By rotating the folder 20 rearward or forward about the hinge means, the folder 20 is opened and closed.
These days, in an attempt to allow the folder 20 to be more easily opened and closed, an automatically foldable portable device has been disclosed in the art. In the automatically foldable portable device, the folder 20 can be manually opened and closed, and, at the same time, when an operation button is pressed, the folder 20 can be automatically opened and closed by a motor.
Referring to FIG. 2, there is shown a cross-sectional view taken along the line A—A of FIG. 1, illustrating the conventional folder driving device for a portable device. One end of the hinge housing 25 is connected to a first shaft support part 16 of the body element 10 by the medium of a hinge shaft 30, and the other end of the hinge housing 25 is connected to a second shaft support part 15 of the body element 10 by the medium of cam couplers 35 and 36.
A motor 31 and a reducer 32 are disposed in the hinge housing 25 to provide driving force for compulsively operating the cam couplers 35 and 36 and thereby automatically opening and closing the folder 20.
The cam couplers comprise a hinge cam 36 and a hinge shaft 35. The hinge cam 36 is coupled to the second shaft support part 15 of the body element 10 in a manner such that it is prevented from being rotated and is allowed to be moved in an axial direction while being supported by an elastic member 38. The hinge shaft 35 is connected to an output end of the reducer 32 and faces the hinge cam 36 to determine folder opening and closing positions.
The unexplained reference numerals 33 and 34 represent sensor means for sensing an opened position of the folder 20. The sensor means comprise a sensing plate 33 and a sensing contactor 34 to be brought into contact with the sensing plate 33. Further, the unexplained reference numeral 37 represents a guide ring for guiding movement of the hinge cam 36.
However, the conventional folder driving device constructed as mentioned above suffers from defects in that, since the hinge cam 36 is not mounted in the hinge housing 25, the motor 31 and the hinge shaft 35 must be assembled along with the hinge cam 36 and the elastic member 38, whereby assemblability of the folder driving device is deteriorated, and it is difficult to adequately maintain gaps between component parts to be assembled.
FIG. 3 is a cross-sectional view illustrating another conventional folder driving device for a portable device. In this folder driving device, a motor 42, a gear box 43, a hinge shaft 44 and a hinge cam 45 are all disposed in a hinge housing 25.
Nevertheless, the folder driving device described just above encounters a problem in that, because the motor 42 and the gear box 43 are supported by an elastic member 41 to be moved in an axial direction, a first space which is occupied by the elastic member 41 and a second space in which the motor 42 is to be moved must be necessarily secured, whereby it is difficult to increase a size of the motor 42, and limitation cannot but be imposed to increasing a torque of the motor 42.